Shut-off valve

Changing the shut-off valve on my '84 300D. One MB dealer says i will need 2 gaskets, the other says i need an o-ring. Both want at least $113.00 for the part.

What do i actually need, 2 gaskets or an o-ring? Is this a good price for the part? Fastlane says its unavailiable (will call Phil tomorrow).

BTW, i know about hooking the tab into the IP, so thanks in advance for your warnings!!!